The present application claims priority to Japanese Application No. P2000-152473 filed May 24, 2000 which application is incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
The invention relates to an electrolyte containing an electrolyte salt and a battery using the electrolyte.
2. Description of the Related Art
Recently, in accordance with development in electronic technology, a number of small-size portable electron devices such as VTRs (video tape recorder) with a built-in camera, cellular phones and note-book computers have come into wide use, and miniaturization and lightening of the devices have become the subject. Batteries, specifically, secondary batteries have been put at the stage of development as a portable electric source used for the devices. Especially, lithium-ion secondary batteries have drawn the attention since the batteries can achieve a high energy density. Specifically, thin-type batteries with form features capable of being folded and having high versatility have been actively studied and developed.
In the batteries with form features having the high versatility, for example, a solid-state electrolyte with no chance of liquid leakage is used. As the solid-state electrolyte, for example, a gel electrolyte in which a plasticizer containing an electrolyte salt is held in a high polymer, and a high polymer solid electrolyte in which an electrolyte salt is dispersed onto a high polymer have drawn the attention. A number of reports have been made on the gel electrolyte or the high polymer solid electrolyte. For example, the electrolytes can be prepared using a simple method such as polymerization of solutions containing monomers to be in a gel- or solid-state.
For example, in a battery stacking a positive electrode and a negative electrode with a separator interposed, the electrolyte is prepared by impregnating the separator with a solution containing monomers and then the monomers are polymerized. Also, the electrolyte is prepared by applying a solution containing monomers on a positive electrode or a negative electrode and then monomers are polymerized.
However, in the battery of the related art, a negative electrode collector layer is made of copper (Cu), which becomes a factor for inhibiting the reaction, thereby interrupting a smooth process of monomer-polymerization. As a result, a number of non-reacted monomers remain in the electrolyte and the remained monomers dissolve or react in accordance with the electrode reaction, resulting in deterioration in the charging/discharging efficiency or the charging/discharging characteristic. Polymerization can be promoted by changing the condition such as increasing the reaction temperature. However, if the reaction temperature is increased, the electrolyte is decomposed. As a result, the charging/discharging efficiency or the charging/discharging characteristic is also deteriorated.
The invention has been designed to overcome the forgoing problems. The object of the invention is to provide an electrolyte capable of obtaining an excellent electrolyte and a battery using the electrolyte.
An electrolyte of the invention is prepared by polymerization reaction and contains at least one and more of carboxylic acid, alkali metal carboxylate, and alkaline-earth metal carboxylate.
A battery of the invention comprises a positive electrode, a negative electrode, and an electrolyte. The electrolyte is prepared by polymerization reaction and contains at least one and more of carboxylic acid, alkali metal carboxylate, and alkaline-earth metal carboxylate.
The electrolyte of the invention contains at least either carboxylic acid or carboxylate. Therefore, polymerization of monomers can be smoothly processed even under the existence of copper in the case where the electrolyte contains the high polymer obtained by, for example, polymerization of monomers. As a result, an excellent quality of electrolyte with little amount of remained monomers can be obtained.
The battery of the invention exhibits an excellent battery characteristic since the battery comprises the electrolyte of the invention.
Other and further objects, features and advantages of the invention will appear more fully from the following description.